Firstly, transfer rates are "only" about 30MB/s, both with Samba and by
FTP. This is in both directions. This seems a bit low?

Both aren't good network benchmarks because they are limited by the
application performance, disk speed, etc..
Please use the "netio" or "ttcp" package from "pkgsrc" for network
benchmarking.

Secondly, I have noticed that whilst idle "TLB shootdown I" (there are
two of these, dual core, I believe this is the one for CPU #1) is next
to nothing. It'll go up to 5 every so often and then just not register
for the rest of the time. Whilst doing an FTP... it goes through the roof:

[...]
What version of NetBSD are you using?
Kind regards

Sorry, I forgot to mention the more important stuff.
(markie@homeserver:ttyp0)-(~)$ uname -a

I think I mentioned it was a PCI-E card, and it's on a Gigabyte G31M-S2L
board with a dual core E2180. It does have an onboard RealTek gigabit
NIC, but it appears to be a bit dodgy... hence buying the Intel one!